Related Features

Skin Care Delivery Systems

Today’s sophisticated ingredients call for sophisticated delivery systems. Suppliers explain how they are rising to the challenge.

Tom Branna
Editorial Director

Not too many years ago, skin care was as simple as soap and water with, perhaps, a little moisturizer thrown into the mix. Seems almost quaint, doesn’t it? Today, cosmetic chemists work with hydroxy acids, peptides and a whole range of high-tech materials that promise to do much more than clean skin and trap moisture. But even the most efficacious material won’t do much good if it never reaches its intended target, which makes skin care delivery systems more critical than ever in determining a product’s effectiveness.

“In this day and age, we have more ingredients that have specific targets on the skin,” explained Jon Packer, president of Centerchem. “If what you put on the skin doesn’t get to the intended location, it certainly won’t have the desired activity.”

The hardest part is getting the active to the right location within the skin, agreed Dan Beio, vice president, research and development, RITA.

“Even the use of lipid material doesn’t mean that the barrier is now restored and all is on the road to recovery.”

According to Mr. Beio, the correct lipids must be chosen, they must be presented to the skin in a fashion that won’t further de-fat the skin, and then they must stay put in the spot where their attention is needed.

“You can spend months researching the correct lipid to restore the barrier, but if you present this to the skin with an emulsion, the emulsifiers and surfactants contained in the product could further damage the barrier by emulsifying the barrier lipids and your actives away from the structure of the skin,” he explained. “They must penetrate into the stratum corneum to fill those voids. The same issue occurs if you are using actives in liposomal form. Emulsifiers and surfactants will dissolve the liposome core, releasing the active and rendering it ineffective.”

To circumvent this problem, Mr. Beio recommends using emulsifying thickeners, such as RITA’s Viscolam AT 100P, which allows for the creation of an emulsion with virtually no emulsifiers.

A Premium on Skin Care

One reason why marketers are searching for effective delivery systems is because the aging consumer base is putting a premium on skin care. According to the NPD Group, Port Washington, NY, sales of prestige skin care products rose 2% to $1.2 billion in the first half of 2008—not bad for an economy in recession. That demand underscores consumers’ willingness to spend money for products that work.

“Enhanced delivery of ingredients is a natural evolution toward more efficacious products. Simply having actives in skin care products and marketing their functionality/efficacy doesn’t satisfy either marketers themselves or consumers any more,” explained Elzbieta Kasprzyk, senior manager, laboratory services, TRI-K. “It is a common knowledge that actives can be delivered into skin even from simple/conventional emulsion but at much slower rate. We are witnessing an increasing market expectation to see the immediate results and consumers seem to be willing to pay a premium for it.”

“As discretionary income becomes more challenged, the fundamentals in skin care, such as facial moisturizers and anti-aging, are currently winning with prestige consumers,” said Karen Grant, NPD’s vice president, in a statement.

Within mass markets, sales of the entire skin care category totaled $2 billion in U.S. supermarkets, drugstores and mass merchandisers, excluding Wal-Mart, for the year ended Feb. 24, 2008, according to data from Information Resources, Inc. (IRI), Chicago. That total includes $605.7 million for facial anti-aging products, $569.6 million for facial cleansers, $345 million for acne treatments, $320.4 million for facial moisturizers and $27.8 million for body anti-aging products.

What’s more, Mintel, a Chicago research firm, estimates sales of anti-aging skin care products will increase 50% in current prices between 2006 and 2011.

Sophisticated Solutions

Regardless of whether these products are applied to the face, hands or body, or sold in department stores or drugstores, more of them rely on increasingly sophisticated delivery systems to put active materials exactly where they are needed most. In fact, industry observers note that an effective delivery system can impart a variety of benefits to a skin care product.

Sarah Teichmüller, business development and marketing manager, Rovi Cosmetics International GmbH, noted that there is a variety of cosmetic active ingredients, such as plant extracts with fantastic stories as well as many vitamins (e.g. retinol) that are tricky to stabilize and formulate.

“Sometimes a great new active has an unbearable smell which can then be solved by encapsulation,” she noted. “Vitamins play an important role in skin protection. But what good is a vitamin that doesn’t even survive the manufacturing temperature or if it does, oxidizes six weeks later in the final formulation?” she asked.

According to Ms. Teichmüller, oxidation issues can force formulators to use vitamin derivatives, many of which are known to have less or even no antioxidative power.

“Liposomal encapsulation could have been one of the solutions to these issues,” she explained. “If, on the other hand you, want a cosmetic active to support collagen synthesis you need to bring it to the dermis in order to perform. Either the active does so by itself or it needs a vehicle.”

Delivery systems have other roles too.

“Enhancing skin delivery enables formulators to achieve targeted and timed release of actives and enhance efficacy and effective concentration at the required site of action, to preserve the stability of active components and minimize irritation potential of certain useful actives,” explained Rajarajeswari Sivalenka, a biochemist with Lipo Chemicals.

Special Delivery

Besides enhancing penetration or minimizing irritation, the right delivery system can even make hard-to-use ingredients easier to formulate. Industry suppliers note that the list of “difficult to deliver” active ingredients is a long one that includes peptides, hyaluronic acid, vitamin C and other vitamins, collagen and essential fatty acids.

“Delivery systems, such as liposomal systems, are important to effectively deliver some peptides,” explained Mr. Packer. “But luckily, many peptides are stable, especially if the formulator does his homework.”

For those that are not, Centerchem offers Decorinyl, created by Lipotec, a tetrapeptide that has been incorporated into a liposomal system for enhanced penetration and increased efficacy. According to the company, Decorinyl regulates fibrillogenesis, controls collagen fibril growth and increases skin suppleness, due to a better cohesion of collagen fibers that provides higher resiliency and improves skin appearance.

Other industry experts contend excellent delivery systems are found in Proactive Solution Renewing Cleanser, which is said to include excellent technology to deliver benzoyl peroxide, and Johnson & Johnson’s Aveeno facial care products, which deliver soy to the skin.

Most recently, Klein-Becker expanded its line of skin care products under the Strivectin umbrella, with the rollout of a neck cream, wrinkle filler, oily skin formula and Phase-2 Dermal Defense Factor, which is billed as the first and only compound specifically developed to protect against wrinkles caused by urban pollution.

The delivery system for Strivectin neck cream is created by an emulsion which includes fatty acids and fatty acid esters that increase the fluidity of the stratum corneum and by a pH that is slightly acidic, which keeps the polypeptides and amino acids in a neutral electrical charge, according to Nathalie Chevreau, director of women’s health, Klein-Becker.

“This allows the small polypeptides and amino acids to penetrate through the lipid layers of the stratum corneum,” she explained.

In contrast, the wrinkle filler is an aqueous gel that contains a combination of hydrolyzed polysaccharide polymers and polyols. The gel forms a cohesive, non-occlusive three-dimensional film at the surface of the skin due to the binding of the hydroxyl groups of the polysaccharides polymer and the hydroxyl and amides groups of the intercellular lipids and ceramides of the stratum corneum. According to Dr. Chevreau, stretching this strong film across the surface of the skin makes the wrinkles less visible.

Who Needs Delivery?

These new product launches underscore the importance of having the correct delivery system. As more anti-aging products hit the market, suppliers are rolling out new systems for a variety of reasons.

“There is always a need for new and better tailored delivery systems or vehicles,” explained Nava Dayan, senior principal scientist/head of research and development skin care, Lipo Chemicals. “The more effective the actives developed, the greater the need for reducing exposure for better effect and lower risk. Using less compound to achieve same effect may be also cheaper.”

Industry experts note that in order to restore the barrier function, active ingredients such as ceramides and sphingolipids must be incorporated into the lipid layer of the stratum cornuem. Similarly, to stimulate protein development, actives must get past the outer layer of the stratum corneum to achieve a “cascade effect” in the skin. But before they start formulating, chemists need to investigate their options.

“Suppliers of delivery systems must understand the dynamics and thermodynamics of ingredients, formulations and the stratum corneum,” explained Mark Chandler, technical manager, skin care innovation, Croda. “A tailored approach to individual ingredients is key to success. An ingredient must get into the formulation, out of the formulation and to the targeted site to be effective.”

But Alain Saintrond, president, Creations Couleurs, suggested that most of the interest surrounding delivery systems is primarily for visual appeal and rarely for performance.

“Most formulators are not really open to thinking that skin care can actually bring benefits to consumer's skin,” he told Happi. “Indeed, they see few results with classic formulations (that are) rich in emulsifiers and preservatives.”

Another supplier echoed with Mr. Saintrond’s assessment, noting that few finished products on the market truly provide excellent delivery of actives to the skin. One surprising exception, he maintained, are self-tanning products, which utilize good delivery technology for water-soluble dihydroxyacetone.

On Safety

Every supplier contacted by Happi noted that all cosmetic delivery systems undergo strenuous safety testing prior to entering the market in order to ensure that active materials are delivered when and where promised.

Cosmetic safety regulations have never been stricter than they are at present,” observed Ms. Teichmüller. “There are no additional risks resulting from delivery systems and their use. If at all, there needs to be a stricter distinction between cosmetic and pharmaceutical actives.”

“Products can be delivered too deep within the skin and wind-up in the capillary bed,” warned Thomas Russo, formulations manager, Lipo Chemicals. To avoid having actives in the bloodstream, he suggested that companies conduct invitro test models with markers to determine the depth of penetration related to skin.

But at the end of the day, active ingredients and their delivery systems, can only do so much.

“Frankly, the efficacy is good, but it only goes so far,” explained Mr. Packer. “We’re not taking 50-year-old skin and turning it into a newborn’s skin. We’re creating meaningful improvements and working with the body’s mechanism to achieve cosmetic benefits.

What’s New from Industry Suppliers?

With demand for effective skin care products on the rise, industry suppliers have rolled out an array of new delivery systems for skin care products.

Lipo Chemical, for example, launched Hylasome EG10, a chemically-crosslinked hyaluronic acid that is a delivery system for water. It forms a film on the skin that holds tightly-bound water and delivers that water to the skin over time. In an ex-vivo study, the stratum corneum contained five times more water 24 hours after treatment with Hylasome EG10 than after treatment with hyaluronic acid at the same concentration, according to the company.

Also new from Lipo is Lipobrite HCA-4, a hydroxycinnamic acid that has been solubilized in PEG-4 to enhance its solublity, bioavailability and skin brightening performance.

Current research at Centerchem is focused on micellular systems and liquid crystal systems. For hair care applications, Centerchem offers a family of cationic liposomes, called Vecorexin, that deliver panthenol to the hair shaft.

RITA has introduced a line of easy-to-incorporate silicone matrix ingredients under the brand name Ritasil.

Photo: Lipo Chemicals, Inc.

“The benefit here is the extraordinary feel you get from silicone ingredients with the skin care ‘lipid barrier’ improvement attributes you get from natural oils,” explained Mr. Beio. “We have entrapped five natural oils (sesame, sweet almond, shea butter, sunflower and safflower) within these concentrated silicone matrices to protect them from oxidation and enhance their ease of formulation. The net result is a skin feel that mimics a silicone powder, with the skin care benefits of natural lipids.”

Rovi researchers are currently working on a delivery system that is coated with a positively charged natural substance. According to Ms. Teichmüller, this delivery system adsorbs so tightly onto the skin’s surface (which is negatively charged) that it takes five washings to come off.

“This system will be used for the encapsulation of UV filters,” she explained. “Through the tight adsorption less filter can be used and the filter strictly remains on top of the skin.”

TRI-K Industries, Inc. supplies delivery systems under trade name of KemSpheres. According to the company, the system is quite flexible and can be adjusted to meet specific customer’s needs. Based on solid lipid nanotechnology, it allows for encapsulation of lipophilic and amphiphilic actives. The actives are encapsulated in the solid lipid portion of the system and slowly released onto the skin upon formation of the exceptionally coherent film on the skin. This film can be referred to as “patch-like” so the mechanism of release mimics that of delivery from a patch. The transport of actives into skin deeper layers is based on lateral diffusion.

KemSpheres R (with encapsulated retinol) is the newest addition to the line. Besides enhancing delivery, it stabilizes retinol and significantly reduces skin irritation associated with this active, thus allowing formulators to increase its use level, according to TRI-K.

Croda has been studying the role of emollients, emulsifiers and polar delivery vehicles in ingredient delivery for many years, according to Mr. Chandler. Croda continues to bring new understanding of the role of such lamellar liquid crystal-forming emulsifiers as Arlatone LC and Crodafos CES in delivery, as well as furthering its appreciation of the large role Arlasolve DMI continues to play as a safe delivery vehicle for polar ingredients and difficult-to-dissolve materials.

Creations Couleurs is developing binary systems made to measure. These systems are under patent applications, according to Mr. Saintrond.

“The idea is simply to bring into place at the right time two ingredients which are chemically incompatible, and that create a new function once united,” he explained. “I would call this technique in situ activity for high end skin care.”

Solutions for Wipe-Based Formulas

Evonik Goldschmidt has introduced several delivery systems with applications in personal care wipe products. For example, Tego Wipe DE PF is a ready-to-use concentrate for simple processing of O/W nanoemulsions with an excellent stability profile, according to the company. It is suitable for the formulation of PEG-free impregnating lotions for wet wipes, has excellent makeup removing properties, provides a light, non-oily skin feel and is paraben-free. Tego Wipe Flex gives formulators the flexibility to formulate O/W lotion wipes with various sensorial profiles. Also new is Tego Wipe Lux, which Evonik Goldschmidt bills as innovative EO-free concentrate for cosmetic wet wipes that contains natural cotton seed oil.

Aside from wipes, the company has introduced two new skin care ingredients, too. Tego Emulprot is a natural milk-and-sugar-based emulsifier designed for natural cosmetic O/W emulsions. while Tego Care LTP is billed as a versatile vegetable-based emulsifier blend for cost effective processing of O/W emulsions for skin care, sun care or baby care applications. Tego Care LTP suitable for cold processing of lotions and sprays and for hot processing of creams at a pH 5-8.5, according to the company.

Additionally, Abil Care XL 80 is a new emulsifier providing an outstanding combination of stabilization and sensory benefits, according to Evonik Goldschmidt.

With analysts predicting continued gains in the anti-aging category even as the economy slips, marketers and their suppliers will continue to roll out new products that rely heavily on safe and effective delivery systems.